JET D-T experiments and their implications for ITER

This paper reports the first deuterium-tritium (D-T) fusion experiments in the geometry of the International Thermonuclear Experimental Reactor (ITER), with long pulse length and an ITER-like divertor. It first discusses the technical preparations for these D-T experiments and the issues of loading the vessel walls with tritium and of tritium clean-up. It then discusses important physics results of ELMy H-modes, the standard ITER mode of operation: three ITER reference ICRF heating schemes, second harmonic, tritium (2ω_CT) with and without additional He³ and fundamental minority deuterium in a tritium plasma (ω_CD), have been successfully tested; the present ITER scaling for the L-H threshold power needs to be modified to include a favourable mass dependence (~1/A); and the A^0.41 mass dependence in the ITER scaling for the energy confinement time has to be removed. Finally, world records in fusion, performance are reported: a record fusion energy (14 MJ) in standard ITER ELMy H-mode and records of fusion power (13 MW) and Q(0.6) in hot ion ELM-free H-mode, which also show clear signs of α-particle heating. In optimised shear mode, strong internal transport barriers were established and 8.2 MW of fusion power was produced. So far; no α-particle driven Alfvenic instabilities have been observed in these high fusion power discharges